1. Field of the Invention
The present invention relates to a thermal printer for use as a label printer or the like. More particularly, it relates to a thermal printer which performs recording by means of transmitting the rotation of a drive motor to a ribbon take-up roll so as to take up a thermal transfer ribbon, feeding a sheet of paper on top of the thermal transfer ribbon, both the paper and the ribbon being fed, pressing a thermal head to a platen with the sheet of paper and the ribbon grasped therebetween, and supplying an electric current to the thermal head on the basis of recording signals to that the ink of the thermal transfer ribbon is transferred to the sheet of paper.
2. Background Information
Hitherto, in this type of thermal printer, since a thermal transfer ribbon is fed and taken up along with a sheet of paper even when a blank portion which needs not be printed exists in one line, a portion of the ribbon which corresponds to the blank portion is taken up with that ribbon portion being unused. Therefore, ribbons are consumed wastefully and running costs are high. Hence, there are previously been available a thermal pitcher in which a motor for rewinding a thermal transfer ribbon is provided to eliminate such a wasteful consumption of ribbons. After an unused portion of a thermal transfer ribbon which is fed together with the feed of a sheet of paper is taken up, a thermal head is separated from a platen so as to release the mutually pressed contact of the thermal transfer ribbon and the paper sheet. The taken-up, unused ribbon is then rewound to a supply side by means of the above rewinding motor so that it is supplied once more.
In such a thermal printer, however, a motor for rewinding a thermal transfer ribbon and parts related to it are required, and manufacturing costs therefore rise. Also, it has drawbacks in that time is required to rewind a once taken-up, unused thermal transfer ribbon, and printing speed decreases by such time. In addition, there are problems in that when a rewound thermal transfer ribbon is used again, the thermal transfer ribbon is wrinkled during the re-supply operation if the rewound state is poor, and hence printing quality decreases.
Accordingly, an object of the present invention is to prevent the increase in costs thereof and to prevent a decrease in printing speed and in printing quality.